One step synthesis of core/shell nanocrystal quantum dots

Abstract

Disclosed herein are compositions and one-step synthesis of core/shell nanocrystal quantum dots. In an embodiment, a method of making a nanocrystal includes mixing at least one cationic precursor, at least one anionic precursor, and at least one solvent to form a mixture, heating the mixture, precipitating the mixture to form a nanocrystal precipitate, and isolating the nanocrystal precipitate. The formed nanocrystal comprises an outer shell encapsulating an inner core and exhibits substantial crystallinity, monodispersity, and reproducibility.

1 . A method of making a nanocrystal quantum dot, the method comprising:
 mixing at least one cationic precursor, at least one anionic precursor, and at least one solvent to form a mixture;   heating the mixture;   precipitating a nanocrystal quantum dot precipitate; and   isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot comprises an outer shell encapsulating an inner core and wherein the nanocrystal quantum dot exhibits substantial crystallinity, monodispersity, and reproducibility.   
     
     
         2 . The method of  claim 1 , wherein the mixing comprises mixing the at least one cationic precursor selected from the group consisting of a group II metal, a group III metal, a group IV metal, and a combination thereof with the at least one anionic precursor and the at least one solvent. 
     
     
         3 . The method of  claim 1 , wherein the mixing comprises mixing the at least one cationic precursor, the at least one solvent, and the at least one anionic precursor selected from the group consisting of a group V metal, a group VI metal, and a combination thereof. 
     
     
         4 . The method of  claim 1 , wherein the mixing comprises mixing the at least one cationic precursor, the at least one anionic precursor, and the at least one solvent selected from the group consisting of a coordinating solvent, a non-coordinating solvent, and a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the mixing comprises mixing the at least one cationic precursor, the at least one anionic precursor, and the at least one solvent comprising a coordinating solvent selected from the group consisting of a phosphine, a phosphine oxide, a phosphonic acid, a phosphinic acid, a long chain carboxylic acid, an amine, a thiol, polyethylene glycol, a pyridine, a furan and combinations thereof. 
     
     
         6 . The method of  claim 5 , wherein the mixing comprises mixing the phosphine and the cationic precursor in a weight to weight ratio of about 0.001:1 to about 10:1. 
     
     
         7 . The method of  claim 1 , wherein the mixing comprises mixing the at least one cationic precursor, the at least one anionic precursor, and the at least one solvent comprising a non-coordinating solvent selected from the group consisting of octadecene, octadecane, tetradecane, squalane, and combinations thereof. 
     
     
         8 . The method of  claim 1 , wherein the mixing comprises mixing the at least one cationic precursor, the at least one anionic precursor, and the at least one solvent comprising a long chain carboxylic acid selected from the group consisting of butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, myristoleic acid, palmitoleic acid, gadoleic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, parinaric acid, aracidonic acid, timnodonic acid, brassic acid, clupanodonic acid, and combinations thereof. 
     
     
         9 . The method of  claim 8 , wherein the mixing comprises mixing the long chain carboxylic acid solvent and the cationic precursor in a weight to weight ratio of about 1:1 to about 4:1. 
     
     
         10 . The method of  claim 1 , wherein the isolating comprises isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot comprises an outer shell encapsulating an inner core, and wherein the nanocrystal core is selected from the group consisting of a group II-VI compound, a group II-V compound, a group III-VI compound, a group III-V compound, a group IV-VI compound, a group compound, a group II-IV-VI compound, a group II-IV-V compound, and combinations thereof. 
     
     
         11 . (canceled) 
     
     
         12 . The method of  claim 1 , wherein the isolating comprises isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot comprises an outer shell encapsulating an inner core, and wherein the nanocrystal shell is selected from the group consisting of a group II-VI compound, a group II-V compound, a group III-VI compound, a group III-V compound, a group IV-VI compound, a group I compound, a group II-IV-VI compound, a group II-IV-V compound, and combinations thereof. 
     
     
         13 . (canceled) 
     
     
         14 . The method of  claim 1 , wherein the isolating comprises isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot comprises an outer shell encapsulating an inner core, and wherein the nanocrystal quantum dot has a core selected from the group consisting of CdSe, CdS, CdTe, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, AlN, AlP, AlAs, AlSb, GaSe, TlN, TlP, TlAs, TlSb, PbS, PbSe, PbTe, and a combination thereof; and
 a shell selected from the group consisting of Zn x Cd 1-x S, Mg x Cd 1-x S, Ca x Cd 1-x S, Sr x Cd 1-x S, Ba x Cd 1-x S, Hg x Cd 1-x S, Sc x Cd 1-x S, Al x Cd 1-x S, Ga x Cd 1-x S, In x Cd 1-x S, Mn x Cd 1-x S, Fe x Cd 1-x S, Ni x Cd 1-x S, Cu x Cd 1-x S, Mo x Cd 1-x S, Pd x Cd 1-x S, Ag x Cd 1-x S, Pt x Cd 1-x S, Au x Cd 1-x S, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, MgS, MgSe, MgTe, HgS, HgSe, HgTe, PbS, PbSe, PbTe, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, TlN, TlP, TlAs, TlSb, and a combination thereof.   
     
     
         15 . (canceled) 
     
     
         16 . The method  claim 1 , wherein the isolating comprises isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot has an average diameter of about 2 nanometers to about 10 nanometers. 
     
     
         17 . The method of  claim 1 , wherein the isolating comprises isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot exhibits a quantum yield (QY) of about 60% to about 90%. 
     
     
         18 . The method of  claim 1 , wherein the isolating comprises isolating the nanocrystal quantum dot precipitate to obtain the nanocrystal quantum dot, wherein the nanocrystal quantum dot exhibits an emission wavelength of about 400 nanometers to about 2000 nanometers. 
     
     
         19 . (canceled) 
     
     
         20 . The method of  claim 1 , wherein heating the mixture comprises heating the mixture to a temperature of about 170° C. to about 300° C. at a rate of about 2° C. per minute to about 50° C. per minute for about 30 minutes to about 4 hours. 
     
     
         21 - 22 . (canceled) 
     
     
         23 . The method of  claim 1 , wherein the precipitating comprises cooling the mixture to a temperature of about −50° C. to about −100° C. and adding a polar solvent. 
     
     
         24 - 25 . (canceled) 
     
     
         26 . The method of  claim 23 , wherein adding the polar solvent comprises adding the polar solvent selected from the group consisting of dichloromethane (DCM), tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, formic acid, methanol, ethanol, butanol, and combinations thereof. 
     
     
         27 . The method of  claim 1 , wherein isolating the nanocrystal quantum dot precipitate comprises isolating the precipitate by centrifuging the mixture. 
     
     
         28 - 31 . (canceled) 
     
     
         32 . A method of forming a nanocrystal comprising an outer shell encapsulating an inner core, the method comprising:
 contacting a solvent comprising a first mixture of trioctylphosphine, stearic acid, and 1-octadecene with a second mixture comprising CdO, at least one cationic precursor, and at least one anionic precursor to form a third mixture;   heating the third mixture;   precipitating to form a nanocrystal precipitate; and   isolating the nanocrystal precipitate to obtain the nanocrystal.   
     
     
         33 . The method of  claim 32 , wherein the contacting comprises contacting the solvent comprising the first mixture of trioctylphosphine, stearic acid, and 1-octadecene with the second mixture comprising CdO, the at least one anionic precursor, and the at least one cationic precursor selected from the group consisting of a group II metal, a group III metal, a group IV metal, and a combination thereof. 
     
     
         34 . The method of  claim 32 , wherein the contacting comprises contacting the solvent comprising the first mixture of trioctylphosphine, stearic acid, and 1-octadecene with the second mixture comprising CdO, the at least one cationic precursor, and the at least one anionic precursor selected from the group consisting of a group V metal, a group VI metal, and a combination thereof. 
     
     
         35 . The method of  claim 32 , wherein the contacting comprises contacting trioctylphosphine and the cationic precursor in a weight to weight ratio of about 0.001:1 to about 10:1. 
     
     
         36 . The method of  claim 32 , wherein the contacting comprises contacting stearic acid and the cationic precursor in a weight to weight ratio of about 1:1 to about 4:1. 
     
     
         37 . The method of  claim 32 , wherein isolating the nanocrystal precipitate comprises obtaining the nanocrystal wherein the nanocrystal core comprises a group II-VI compound, a group II-V compound, a group III-VI compound, a group III-V compound, a group IV-VI compound, a group I-III-VI compound, a group II-IV-VI compound, a group II-IV-V compound, or combinations thereof. 
     
     
         38 . (canceled) 
     
     
         39 . The method of  claim 32 , wherein isolating the nanocrystal precipitate comprises obtaining the nanocrystal wherein the nanocrystal shell comprises a group II-VI compound, a group II-V compound, a group III-VI compound, a group III-V compound, a group IV-VI compound, a group I-III-VI compound, a group II-IV-VI compound, a group II-IV-V compound, or combinations thereof. 
     
     
         40 - 42 . (canceled) 
     
     
         43 . The method of  claim 32 , wherein isolating the nanocrystal precipitate comprises obtaining the nanocrystal wherein the nanocrystal has an average diameter of about 2 nanometers to about 10 nanometers, and the nanocrystal exhibits a quantum yield (QY) of about 60% to about 90%. 
     
     
         44 . (canceled) 
     
     
         45 . The method of  claim 32 , wherein isolating the nanocrystal precipitate comprises obtaining the nanocrystal wherein the nanocrystal exhibits an emission wavelength of about 400 nm to about 2000 nm. 
     
     
         46 . (canceled) 
     
     
         47 . The method of  claim 32 , wherein heating the third mixture comprises heating the third mixture to a temperature of about 170° C. to about 300° C. at a rate of about 2° C. per minute to about 50° C. per minute for about 30 minutes to about 4 hours. 
     
     
         48 - 49 . (canceled) 
     
     
         50 . The method of  claim 32 , wherein the precipitating comprises cooling the third mixture to a temperature of about −50° C. to about −100° C. and adding a polar solvent. 
     
     
         51 - 53 . (canceled) 
     
     
         54 . The method of  claim 32 , wherein isolating the nanocrystal precipitate comprises isolating the precipitate by centrifuging the mixture. 
     
     
         55 - 58 . (canceled) 
     
     
         59 . The method of  claim 1 , wherein the method can be carried out as a one-pot reaction to obtain the nanocrystal quantum dot precipitate.